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Back to t7bpc in t5

5K views 28 replies 10 participants last post by  liketheword 
#1 ·
Well, after 2 years of running the greddy profec b electronic boost controller, I finnally switched back to a trionic controlled bpc. Now that tuning is available, it does not make sense to run the ebc any longer.

I made the changes in the ecu and in the sw frequency and then wired up the t7 bpc. I had a few hick-ups because I had had the connector cut off long ago, but with some help from the finish guys, I was able to figure out the wiring and get my new t7bpc working.

I am very happy to have the boost controll back in the hands of the ecu and it seems to spool just as fast as the ebc and I have been able to limit first and second gear so its on the verge of spinning, but not quite and then when I go into third and up, its up to 25psi+ and its off to the races.

THis is going to help with racing since I will be able to concentrate on launching the car and shifting and not when to try and switch to high boost with my remote button. I am so glad I took the time to switch it over to the t7bpc and with the maptun style pid maps, t7bpc, the boost is strong, yet does not overshoot at all, I get no boost chatter while spooling and am very happy with this mod.

The fact the t7bpc's cost 49 bucks is the biggest plus, its a more durable design too.

John
 
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#4 ·
You have to do a few things, you have to lift a very small pin on one of the parts on the ecu, then you have to solder a bridge across two points in the ecu, then you have to change the frequency in the bin file to match some t7 settings.

Once all that is done, you then take a old t7 wiring harness and you can make a t5 to t7 adpater or you can just cut the t5 end off the wiring harness and wire up the t7 connector. You can also use one from a t5 harness, I think its the cam sensor connector.

That is about it.

John
 
#6 ·
Yea, it was a little tricky for me becaus my 1995 ng900 has two green/black wires and one blue one, its not like all the pictures of the 9k connectors, they have a blue a green red and I think a green yellow, so it was confusing for me, but I got it all working and got my first two gears dialed in and its working great now.

It does make a little more noise than the t5bpc, you can hear it clicking here and there, but its not a huge deal.

I will now be able to dial in the first two gears for drag racing at the track with my drag radials. That should help a lot. The clutch still slips, but I have a new spec stg3+ waiting to put in as soon as I get the time to swap it all out again.

John
 
#11 ·
I can't take credit for figuring this out, just following other people's work and spreading the word.

They do say that the t7bpc is more consistant, controls boost more acurrately and is better at avoiding things like over-shoot. It is a better design and does not seem to wear out like the t5 valves.

If I had good working t5 bpc's and was not having issues, I would not make the change, but since I have 4 on my shelf that are all bad and sticky, I did not want to pay another 263.00 plus shipping and they now do not warranty the t5 bpc's without pictures of a stock airbox, etc.

I have to say my boost control is very consistant, no over-shoot, which part of is the pid boost maps I use, part of it probably is the better designed t7bpc. It is very smooth and it seems to spool just as fast as my greddy profec and seems to lock the boost in pretty darn good.

I am very happy with it and feel better knowing if I get bad gas or have a plug or di fail, the ecu should pull out boost if there is knock and save the motor/head-gasket, etc.

The biggest part is being able to map first and second gear seperately so I can make my car run right on the edge of traction and then let it rip in third gear and up. With 11psi base boost and gt3076wg, I only reach about 24-25psi in 75F weather. The clutch lets loose at about 27psi, so that is just fine for now and once I get the new stage 3+ clutch in the car, I will probably increase the base boost to 15psi and go for 28psi or so and do a few spins at 80mph in third gear:cool:

John
 
#12 ·
I have been using the Greddy electronic boost controllers for at probably 10 years at track events with my 9000. first the profec A, then the profec B and now with the Profec B spec ll. These products are first rate and operate in exemplirarly fassion. Using the latest Profec B at track events with race gas always allowed me to adjust boost control and boost rise and boost taper to fit the days conditions beyond what I could do with trionic control.
John has however re written the book for me on using the trionic system to acheive the same objectives. At our last track event in Lewistown, Montana, john was able to produce some maps that acheived the same resuts or better using only trionic control.
Interesting fact was that I only needed to flip two switches in my dash pannel to completely overide trionic boost control and switch to greddy control. Three days at the track... I never was even tempted to switch.
Congradulations John on not just your tuning ability but also on relating it to real driving conditions for enthusiasts.
 
#14 · (Edited)
I will put this here and if needed I will start a new thread. (Mods let me know.)

As you know my T5 boost pressure control valve went out on my 99 9-3. Last night JK and I wired up the T7 unit and made both hardware and software adjustments to the ECU. The car still seems to run on base boost. We know the old T5 valve is bad because we tested it in a known good T5 car and got base boost. So, our effort wasn't for nadda. The issue remains that with the new T7 valve we get "clicking" when on boost but, none when the brakes are pressed. This also proved to be true on another T5 99 9-3. So, this seems to be normal operation. To test that the system doesn't have a leak we removed the wastegate hose to the boost pressure control valve and disconnected it electrically. Sure, enough she boosts into the red. That tells us everything hardware wise is fine. (eg. hoses and di are fine)

We are left here thinking the only thing left to do is mod another ECU for the T7 valve and test that in my car. Unless anyone else has more ideas? We are really left kind of scratching our heads on this one.

Let me know if I need to elaborate on this. Your help is appreciated!

Again, thank you to JK for being SO helpful! The MN Saab group wouldn't be what it is w/o him. Almost every major Saab project he has contributed to with time/effort/money and we are all richer for it. Especially GA's cars :p
 
#18 ·
We couldn't find a fuse specifically for the APC. But, we did check anything that could be affiliated w/ the APC. All of the fuses appeared to be visually normal. Mind you this was done in limited light but, that is normally fairly obvious visually. Any idea what fuse specifically would be for the APC?

As for the mosfets when we had the ECU out JK checked those and again visually everything looked fine to both of us. Doesn't mean that they haven't failed though... Do you know of a way to test them? We will only really know if it is ECU related if we mod another T5 ECU and swap that in. That's all we can think of right now.
 
#24 ·
You can test the ohm resistance to the bpc and if it test fine, the mosfets are fine. I had one ecu board that would not work, modded another, got boost just fine.

You measure trionic pin 2 to ground
You measure trionic pin 26 to ground

If you get 0 ohm, the fet mosfets are fried, otherwise they are working.

John
 
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